Core drill



2 Sheets-Sheet l MHH J. H4 HOWARD ET AL.

CORE DRILL Filed Dec. l,

April 2s, 1936 April 28, 1936. J. H. HOWARD ET AL 2,038,791

CORE DRILL Filed Dec. l, 1955 2 Sheets-Sheet 2 PWM/M Patented Apr. 28, 1936 UNITED sTATEs 2,038,791 com; DRILL John H. Howard, Huntington Park, and William H. Maxwell, Beverly Hills, C

ahf., assignors to Globe Oil Tools Company, Los Nietos, Calif., a corporation of California Application December 1, 1933, Serial No. 700,506

4 Claims. (Cl. Z55-72) 'I'his invention relates to a well drilling tool and relates more particularly to a well core drill. It is a general object of the invention to provide a practical, improved core drill embodying a positive, dependable and effective core catching and retaining means.

It is another object of the, invention to provide a core drill embodying a core catching means that may be positively operated into elective holding and retaining engagement with the core without manipulating the drill or the string of pipe carrying the drill.

It is another object of the invention to provide a. core drill involving a novel and particularly effective hydraulically operated core catching means.

It is another object of the invention to provide a core drill including a core catching means that does not engage the core or in any manner interfere with the core during the drilling operation and that may be controlled or governed from the upper end of the well.

'.It is another object 'of the invention to provide l a core catching means that is positively operated by longitudinal movement of the inner core receiving barrel of the drill without movement of the outer barrel of the drill.

It is another object of the invention to provide a core drill including an inner barrel that is movable longitudinally in the outer barrel and means for hydraulically operating the inner barrel downwardly to positively operate the core catching means. In the drill of thepresent invention the weight of theginner barrel assists the hydraulic means in actuating the core catcher.

It is another object of the invention to provide a core drill including an hydraulic core catcher operating means that does not interfere with the normal ow of circulation iiuid during the drilling operation. I I

It is another object ofthe invention to provide a core drill having simple, sturdy core gripping and supporting dogs that are positively forced into gripping and supporting engagement with the core by an hydraulic operating means.

It is a. further object of the invention to prol vide a core drill of the character mentioned inthe invention throughout which description reference may be had to the accompanying drawings, in which:

Fig. l is a longitudinal detailed sectional view of the core drill provided by the invention illustrating the inner barrel in the latched position where the core engaging dogs are in their unactuated positions. Fig. 2 is a View similar to Fig. 1`showing the inner barrel in its down position and the dogs in their actuated'positions. Figs. 3, 4 and 5 are enlarged transverse detailed sectional views taken substantially as indicated by lines 3-.3, 4 4 and 5-5 respectively on Fig. 2, and Fig. 6 is a. moreY or less diagrammatical view illustrating thedrill of the present invention in operation in a well' on the lower end of a drilling string. y

The core drill Iprovided by this invention inv cludes generally an outer barrel I0 having a bit head I I on its lower end, core gripping and supporting dogs l2, an inner barrel I3 adapted to move downwardly to actuate the dogs I2, means i4 releasably holding the inner barrel I3 againstV movement, and hydraulic means I5 for releasing the means It and for moving the inner barrel I3 downwardly to actuate the dogs I2. 25

The outer barrel I0 is an elongate tubular member adapted to be attached to the lower end of a string P of drill pipe, or the like. A connecting member or sub I6 is provided on the upper end of the barrel I0 to form a part thereof and to facilitate connection with the lower end of the drilling string p. The sub I6 is providedV with a central longitudinal uid passage I1 for conducting circulation iuid downwardly from the drilling string as will be more fully described. A sub Iii is provided on the lower end of the outer barrel I0 to carry the bit head II. 'I'he sub I8 is provided at its lower end with a downwardly projecting screw threaded pin I9.

The bit head II is provided on the lower end of the outer barrel I0 to make an annular cut in the earth formation and leave the core C. The bit head Il is a tubular member which may be threaded on the pin I9. In accordance with the broader aspects of the present invention, the bit head I I may be provided with any suitable form of cutting means. In the particular caseA illustrated in the drawings, aplurality of downwardly and outwardly projecting cutting blades is provided on the b`it head I I. Each of the blades 20 may have a downwardly projecting tooth 2i at its inner end to cut or trim the core C to pass upwardly into the bit head and inner bary rel. An annular-groove 22 is provided in the bithead II at-the lower end of the-pinlS and fluid passages 23 extend downwardly from the groove 22 to discharge from the lower end of the bit head in iront of the several blades 20. The central opening of the bit head is provided with two vertically spaced annular shoulders 24 and 25. The portion 26 of the bit head opening below the lower` shoulder 25may be inclined downwardly and inwardly.

The core gripping and supporting dogsy I2 are positioned or mounted in the bit head I I in positions to be actuated by the inner barrel I3 when it is moved downwardly by the hydraulic actuating means I5. 'There is preferably a plurality of dogs I2 provided in the bit head I I at circumferential spaced points. Inl the particular form of the invention illustrated in the drawings, there are four equally spaced dogs I2 carried by blocks 28 arranged or inset in openings 29 in the wall of the bit head. In practice the blocks 28 may be welded in place. Sockets 3D are provided in the inner sides of. the blocks 28 to receive the end portions of the dogs I2. The blocks 23 may be positioned soV that their inner sides occur at the tapered portion 26 of the bit head opening in which case their inner sides may have the same `inclination as the said portion of the opening.

Pivotv pins or screws 32 extend through transverse openings in the dogs I2 to pivotally support them in the` sockets 36. The screws 32 are carried in transverse openings in the bit head I I and have their heads countersunk. The dogs I2 project inwardly from the blocks 2B and the upper and lower sides of their projecting portions converge to comparatively sharpouter edges. In practice the upper and lower sides `of the dogs are flat, as illustrated in the' drawings. Means are provided for normally yieldingly holding the dogs I2 in u-p positions where they do not interfere with the core C during the drilling operation. A notch 33 is provided in the pivoted end of each dog I2 and carries a torsional spring 34 which yieldingly urges the dog to the up or unactuated position. When the dogs are in their up positions their lower sides are substantially vertical and have clearance with the core C.

The inner barrel I3 is disposed longitudinally in the outer barrel I and is concentric with the outer barrel. The inner barrel I3 is spaced from the interior from the outer barrel III providing a longitudinal annular fluid passage 35 between the two barrels. The main section or body of the inner barrel I3 is of substantial length and in the case illustrated has comparatively thin walls. In accordance with the invention, the inner barrel I3 is supported for limited longitudinal movement relative to the outer barrel IG. A ring or collar 36 is provided on the lower end of the inner barrel I3 and is shiftably or slidably supported in the bit head II.. The collar I3 may be attached to the inner barrel in any suitable manner. In the particular construction illustrated, the collar 36 is Welded on the lower end portion of the inner barrel. The exterior or Iperiphery of the col-lar 36 is stepped having an upper portion 31 to operate in the bit head between the lower end of the pin I9 and the shoulder 24 and a lower portion 38 operating in the bit head opening between the shoulders 24 and 25. A bearing ring 39 may be provided on the portion 31 to engage the lower end of the pin I9. A multiplicity of. circumferentially spaced ports 40 is provided in the portion 31 to pass fluid from the annular passage 35 downwardly to the groove 22 in the bit head. The lower end of the collar 36 is provided with an internaldownwardly and outwardly inclined or upper end of the inner barrel I3.

curved face 4I to cooperate with the dogs I2 to positively pivot the dogs downwardly and inwardly into the core C when the inner barrel I3 is moved downwardly with respect to the outer barrel. The face 4I is -such that it has eiective cooperation with the flat upper sides of the dogs I2.

A tubular head or guide 42 is provided on the The lower portion of the guide 42 may fit into the inner barrel I3 and may be connected with the inner barrel by welding. The guide 42 projects upwardly from the inner barrel I3 to slidably iit into the passage I1 of the sub I6. The upper end of the guide 42 is open to receive thel circulation uid that is pumped downwardly through the drilling string P by the pumpv X at the upper end of the well. Lateral ports 43 are provided in the walls of the guide 42 to communicate with the annular fluid passage 35 so that the uid may pass downwardly from the guide 42 into the passage 35. A valve seat 44 is provided in the lower portion of the passage 45 in the guide 42. The valve seat 44 may be screw threaded in the passage 45. A ball 46 is provided to cooperate with the seat 44 to prevent the downwardly flowing circulation uid from entering the upper end of the inner barrel I3. The ball 46 is adapted to move upwardly from the seat 44 to permit iiuid to be displaced from the inner barrel I3 as the core is received in the inner barrel. In the preferred construction, the inner barrel I3 is keyed or splined to the outer barrel to rotate therewith. In the embodiment of the invention being described keys or splines 41 are provided on the guide 42 to slidably lcooperate with keyways 48 in the sub I6 to key the inner barrel to the outer barrel.

The means I4 for holding the inner barrel I3 in its up position is in the nature of a releasable latch means which positively retains the inner includes a latch 50 carried by the sub I6 for' cooperating with the guide 42. A recess I is provided in the interior of the sub I6 to carry the latch 56. A pivot pin or screw 52 passes through the recess 5I and an opening in the latch to pivotally support the latch in the recess 5I. A spiralled spring 53 surrounds the pivot screw, 52 and acts on the latch 50 to normally yieldingly urge the latch outwardly to cooperate with an opening 54 in the wall of the guide 42. The nose or active portion of the latch 50 is shouldered t0 cooperate with the upper wall of the opening 54 in a manner to dependably hold the inner barrel I3 against downward movement during the drilling operations, etc. The latch 5I) is proportioned to project into the iiuid passage 45 of the guide and its projecting portion has a downwardly and inwardly inclined face 55. As the drill is run into the well and during the drilling operation, the latch 56 cooperates with the opening 54 to hold the inner barrel I3 in the position illustrated in Fig. l of the drawings so that the dogs I2 are retained in their up and inactive positions by the springs 34.

The hydraulic actuating means I5 is adapted to release the latch 50 and immediately thereafter force or move the inner barrel I3 downwardly to actuate the dogs I2. The means I5 includes a.

2,035,791 valve seat 60 in the fluid passage 45 of the guide.`

drill string P to release the latch 50 andto cooperate'with the seat 60. The valve member 6I is preferable in the form of a ball proportioned to fairly accurately t the passage 45 above the seat 60. 'I'he seat 60 is shaped to effectively receive y the ball 6I so that the ball closes thepassage 45 against the downward flow of fluid. When a sufiicient or desired amount of core C has been drilled or taken the ball or closure member 6I may be introduced into the drilling string P at the upper end of the well to drop or be pumped downwardly so as to enter the upper end of the guide passage 45. l Ihe pressure on the pumped circulation fluid forces the ball 6I downwardly through the passage 45 to pivot the latch 50 outwardly and disengage it from the opening 54 and then come to rest on the seat 60 where it prevents downward flow through the passage. The uid pressure then'positively forces the released' inner barrel I3 .downwardly to actuate or pivot the dogs I2 inwardly into the core C to obtain a dependable gripping or supporting engagement with the core.

'I'he invention provides means for informing the driller when the dogs I2 have been fully actuated which means automatically renews or starts the circulation of fluid through the tool immediately after the actuation of the dogs. circumferential spaced openings or ports 'I0 lare provided in the wall of the guide 42 and are positioned so as to move into communication with the upper end of the annular passage when the barrel I3 reaches its final down position. The ports 10 are closed when the inner barrel I3 is held in its up or normal position by the latch 50.

It is believed that the operation of the tool provided by the present invention will be readily apparent from the foregoing detailed description. The core drill is run into the well on the drilling string P with its parts in the positions illustrated in Fig. l of the drawings. The latch 50 dependably holds the inner barrel I3 in its up position, during the running of the tool into the well and during the drilling operation. During the drilling the bit head I I makes an annular cut `or bore in the formation `providing the core C which is received by the inner barrel I3. Circulation fluid is pumped downwardly through the drilling string P to discharge from the ports 23 at the lower end of the bit head. The circulation fluid `'news downwardly through the passage 45 of the guide42 to enter passage 35 and then passes downwardly through the ports and groove 22 to finally discharge from the ports 23. When a core C of suiiicient length has been cut or obtained thel rotary drilling is suspended and the ball or closure member 6I is introduced into the drilling string P at the upper end of the well. After the ball or closurey member 6I has been introduced into the drilling string the circulation fluid is pumped downwardly through the string by the pump X so that the ball 6I is pumped downwardly into the upper end of the guide 42. The closure member or ball 6I forced downwardly through the passage by the uid pressure pivots the latch outwardly to disengage it from the opening 54 and then comes to rest on the seat 60. The pressure of the pumped circulation :duid

, well. The dogs I2 in being ypositively and fully then forces the freed or released inner barrel I3 downwardly so that the inclineduface 4I on its lower end cooperates with the upper sides of the dogs I2 to pivot' the dogs downwardly and inwardly into the core C. 'I'he dogs I2 are thus 5 positively operated into full effective gripping and retaining engagement with the core. It is to be noted that the weight of the inner barrel I3 aids the hydraulic means in its' actuation of the dogs I2. When the inner barrel I3 reaches its down position where the dogs I2 are' actuatedas just described, the ports 10 come into communication with the upper end of the passage 35 so that the circulation fluid is again free to ow downwardly through the tool. With the inner barrel I3 in its l down position, the lower end of the passage 35 is in direct communication with the groove 22. The downward circulation of fluid is temporarily stopped when the ball 6I is on the seat 60 and the inner barrel I3 is being forced downwardly so that the pump X may labor. Upon the opening of the ports 10 to the passage 35 circulation is resumed and the pump X no longer labors, indicating to the driller that the dogs I2 have been fully actuated. After the dogs I2 have been actu-- ated in the manner described, the drill may be raised to break the core C free from the earth formation and may then be withdrawn from the actuated by the downward movement of the inner barrel I3 obtain dependable engagement with the core C and support the core as thetool is withdrawn from the well.

Having described only a typical preferred form of our invention we do not wish to limit ourselves to the specific details set forth. but wish to reserve to ourselves any changes or variations that may appear to those skilled in the art or fall within the scope of the following claims:

Having described our invention, we claim:

1. A core drill to be operated on a string of pipe including, an outer barrel to be connected to the lower end of the string and having cutting means on its lower end for lcutting a core, an inner barrel for receiving the core and having its lower portion guided in the cutting means, the inner barrel being movable longitudinally with respect to the outer barrel, a. core catching dog. carried by the outer barrel at the cutting means, a tubular member on the upper end of the inner barrel slidable in the outer barrel and normally conducting uid passed downwardly through the string, a releasable latch cooperating with the tubular member to suspend the inner barrel in a position where its lower end is clear of the core catching dog, and a part adapted to be dropped through the string to release the latch and close said member against the downward flow whereby pressure applied to the fluid forces the inner barrel downwardly so that its lower end engages and aetuates the core catching dog.

2. A core drill to'be operated on a string of pipe including, an outer barrel to be connected to the lower end of the string, a cutting head on the lower end of the outer barrel for cutting a core, an inner barrel for receiving the core and having its lower portion guided in the head, the inner barrel being movable longitudinally with respect to the outerY barrel, a core catching dog in the cutting head below the lower end of the f inner barrel, a tubular element on the upper end of the inner barrel slidablein the outer barrel t and normally conducting the iiuid pumped downwardly through the string, a latch releasably en- 75 gaging the element to hold the inner barrel in a position where its lower end is spaced above the dog, a valve seat in the tubular element, and a member adapted to be introduced into the string to be pumpeddownwardly through the tubular element to release the latchand then cooperate with the seat to close the element against downward ow whereby the inner barrel may be moved downwardly by fluid pressure so that its lower end engages and actuates the dog.

3. A core drill including an outer-barrel adapt ed to be attached to a tubular operating string, a bit head on the lower end of the outer barrel for cutting a core, a core catching dog pivoted in the bit head, an inner barrel for receiving the core and having its lower portion guided in the head, the lower end of the inner barrel being normally spaced above the dog and being operable to lactulower end of the outer barrel for Icutting a core, an inner barrel for receiving the core and having its lower end guided in the head, the inner barrel being movable longitudinally with respect in the tubular element, and a member adapted to be introduced into the string to be pumped downwardly through the tubular element to release the latch and then cooperate with the seat to close the element against downward flow wherebyv the inner barrel may be moved downwardly by iluid pressure so that its lower end engages and actuates the dog, there being a port in the element opened to pass uid downwardly through the drill upon the inner barrel reaching its down position.

JOI-El H. HOWARD.

AM H. *Mimi l 

